The present invention relates to a hydrocarbon diluent with a low VOC level for use in construction materials, in particular in compositions and materials based on resins and mastics. It also relates to compositions and construction materials containing this diluent.
Numerous products are used in construction materials, for example for floor coverings, paints, wallpapers and mastics for windows or seals of sanitary fittings. They are generally constituted by one or two active components, the viscosity of which is adjusted for the intended application by adding a diluent. These diluents are mixed with at least one resin, a polymer and/or any other paste of high viscosity and have a tendency either immediately, or over time to evaporate and/or degrade, becoming a source of emissions that are often toxic to the environment and more particularly to human and animal health. These emissions are called VOC emissions (VOC: volatile organic compounds). These emissions affect everyday life and constitute an important source of interior pollution of homes, offices and government buildings and of any enclosed space where ventilation is limited and in any case is not directly open to air circulation. These emissions can be considerable at the time of installation but there can also be a longer-term effect from residual volatility that is a function of time or is even connected with progressive degradation of the covering or adhesive composition or mastic. The disadvantage of these materials depends on the amount of materials used, the ventilation of the premises where they are used and the working environment at the time of installation.
The emissions resulting from construction materials are in particular connected with the nature and the emission properties of the diluents used in these materials. These diluents, the purpose of which is to lower the viscosity of the materials temporarily, are classified into at least three types of compounds on the basis of various national or international schemes leading to the attribution of a label or defining the acceptable emission limits for these products: for example AgBB and Blauer Engel in Germany, M1 in Finland, the label “Danish Indoor Climate label” or DICL in Denmark, Emicode, Oeko-Tex, Greenguard or also the protocol of the AFSSET (Agence Française de Sécurité Sanitaire de I'Environnement et du Travail French Agency For Sanitary Safety of Environment and Labour) in France. The classification of the characteristics of these VOC products as defined by the World Health Organization and reflected in standard ISO 16000-6 was used as the basis for the classification presented in Table 1 below:
TABLE 1Boiling point (° C.)Pressure (kPa)length of theISO 16000-6ISO 16000-6hydrocarbon chainsVery VOC or VVOC  <0° C. to 50-100° C. >15 kPa<C6VOC50/100° C. to 240/260° C.>100 kPa C6 to C16Semi VOC240/260° C. to 380/400° C. 0.02 to 10-8 kPaC16 to C22
Within the scope of the present invention, hydrocarbon diluents were sought that have low emission properties, of the low VOC type, capable of preserving the fundamental properties of construction materials, such as floor coverings, adhesive or mastics, i.e. the stability of the material before and after its installation, its ageing, its mechanical properties, its initial appearance, etc. For the PVC pastes used in floor coverings, the use of various types of hydrocarbon solvents is known, such as white spirit, kerosene, isoparaffins or gas-oil: these compounds make it possible to obtain specific rheological properties required for application of the product and a decrease in viscosity of the PVC paste. However, none of these products has characteristics that satisfy the necessary requirements for limiting the level of emission of VOC, semi VOC or very VOC volatile matter.
For simultaneously satisfying the reductions in viscosity and maintaining the properties necessary for the application of these PVC pastes or these mastics, patents WO02/086007 and WO2008/033899 propose the use of esters of fatty acids derived from vegetable oils or these oils themselves mixed with wetting compounds and dispersants whose emissions are zero and which maintain certain expected properties of the final material. Patent WO2004/009738 proposes the use of cuts resulting from the conversion of gas by the Fisher-Tropsch process by hydrocracking/hydro-isomerization of the latter as diluent for silicone-based rubbers.
The present invention has the purpose of using, in construction materials and in particular PVCs used in floor coverings and mastics, diluents that are not of renewable origin, but of fossil origin which make it possible to lower the viscosity of the materials in order to facilitate their handling and their installation but which at the same time can maintain the physical properties required for these materials and their long-term use. Finally, the finished products using these diluents according to the invention must meet the non-VOC requirements of the protocols such as Afsset, AgBB, Blauer Engel, Emicode, Oeko-Tex or Greenguard.
The present invention therefore relates to a hydrocarbon diluent with a low VOC emission for dilution of polymer in construction materials. It is obtained from a mixture of hydrocarbons with a boiling point above 200° C. obtained from the distillation of hydrodewaxed gas-oil cuts. It has a pour point below −15° C. This diluent is a cut with boiling points comprised between 280° C. and 450° C., the sulphur content of which is less than 10 ppm. It contains more than 50% by weight of isoparaffins, and naphthenes up to at most 40% by weight.
By “with low emission of VOC” is meant diluents which, when mixed in construction materials, for example coatings or mastics, meet the requirements of the assessment schemes such as AgBB, Blauer Engel, Emicode, Oeko-Tex, Greenguard or AFSSET. Said diluents combine the advantages of attaining characteristics of the final products identical to those originally manufactured with semi VOC, VOC or very VOC diluents, with the advantages of having a very low volatility, lower than that of the products of the prior art. Preferably, the diluents according to the invention are selected from hydrodewaxed hydrocarbon cuts the viscosity of which at 40° C. according to ASTM standard D445 is greater than 5 mm2/s, more particularly the cuts with a viscosity greater than 7 mm2/s at 40° C.
The hydrodewaxed hydrocarbon cuts selected originate from the hydrodewaxing of various gas-oil cuts obtained by atmospheric distillation, vacuum distillation, hydrotreating, hydrocracking, catalytic cracking and/or visbreaking, or alternatively products originating from the conversion of biomass, optionally after an additional treatment of desulphurization and/or removal of aromatics. The term hydrodewaxed diluent will be used hereinafter in the present description to denote this hydrocarbon diluent. For certain of the applications of the invention, these cuts can have wide distillation ranges of more than 50° C. in the range 280° C.-450° C., or narrower cuts.
Thus, in a preferred embodiment of the invention, the diluent originates from a distillation cut of hydrodewaxed hydrocarbons with a pour point according to ASTM standard D97 below −30° C. In parallel, the flash point of these compounds according to the invention is very high, greater than 140° C. Obtaining a very low pour point favours maintaining the diluent in a mixture, for example with PVC resins or polymers for mastics, and limits or even prevents sweating thereof. Absence of sweating is particularly desirable at low temperature.
The diluents according to the invention are moreover constituted by a majority of isoparaffins and a minority of normal paraffins. The diluent will always comprise more than 10% by weight of naphthenes. Preferably, these diluents obtained from hydrocarbons have been highly hydrodewaxed and therefore contain more than 65% by weight of isoparaffins and less than 10% by weight of normal paraffins. The presence of naphthenes in their composition distinguishes them from other products constituted only by isoparaffins and paraffins that are used in the same applications. Preferably, these hydrodewaxed diluents will contain at least 20% by weight of naphthenes. Typically, within the scope of the present invention, diluents are preferred the naphthene content of which varies from 20 to 35% by weight of the diluent.
More generally, the diluents according to the invention are obtained from hydrocarbons with chain lengths predominantly greater than 16 carbon atoms. Thus, this diluent is composed of less than 65% by weight of hydrocarbons having a chain length comprised between 16 and 22 carbon atoms which are known to be semi-VOC hydrocarbons, and more than 30% by weight of hydrocarbons having a chain length greater than 22 carbon atoms that are non-VOC, as they are non-volatile or of low volatility. In a preferred embodiment, the diluent is composed of less than 50% by weight of hydrocarbons having a chain length comprised between 16 and 22 carbon atoms, and more than 40% by weight of hydrocarbons having a chain length greater than 22 carbon atoms. These hydrocarbons with chain lengths greater than C22 correspond to hydrocarbons containing chains from C23 to at most C30, in order to preserve compatibility with the polymers, which deteriorates as the molecular weight increases.
Moreover, these diluents according to the invention comprise less than 10 ppm of sulphur, preferably less than 2 ppm of sulphur. Their content of aromatics is less than 500 ppm.
As these diluents can be mixed with other compounds, the present invention also relates to a composition of diluents with a low VOC emission. This composition, the second subject of the invention, mainly comprises hydrodewaxed hydrocarbons as described above, but also hydrocarbons constituted by the conventional diluents such as acids and esters of fatty acids with carbon chains with more than 16 carbon atoms, hydrotreated and/or hydrocracked cuts of the gas-oil type with a boiling point comprised between 280 and 450° C. Of course, the cut range adopted for these conventional diluents will be adapted by a person skilled in the art to the main hydrodewaxed diluent with a low VOC. The mixtures thus prepared for obtaining diluent compositions with a low VOC will contain more than 50% by weight of isoparaffins and less than 20% by weight of normal paraffins. The level of naphthenes present will be comprised between 10 and 30% by weight.
The preferred diluent compositions will comprise more than 60% by weight of isoparaffins and less than 10% by weight of normal paraffins, the difference representing the naphthenes that are present. Within the scope of this embodiment of the present invention, the diluent composition will comprise more than 40% by weight of hydrodewaxed diluent, and preferably more than 60% by weight. As for the diluent according to the invention, alone, the composition will comprise less than 65% by weight of hydrocarbons having a chain length comprised between 16 and 22 carbon atoms, and more than 30% by weight of hydrocarbons having a chain length greater than 22 carbon atoms.
A third subject of the invention is the use of the hydrodewaxed diluent according to the invention alone or in combination with at least one conventional diluent for the dilution of resins used for the manufacture of construction materials. The diluents used alone or in combination with a conventional diluent do not alter any of the physical characteristics of the formulations of resins in which they are used, in particular the thermal stability, the optical and mechanical properties and the volatility at 70° C. of the finished product. Moreover, the VOC emissions from the finished products containing them meet the AgBB, Blau Engel, Emicode, Oeko-Tex, Greenguard or Afsset requirements.
The term “resins” as used here means PVC resins, which are added to PVC pastes (or Plastisols) used in the manufacture of floor coverings, coatings for threads or textiles, wallpapers, flexible films, tarpaulins, mastics, etc. These pastes are obtained by the homopolymerization of polyvinyl chloride or PVC, or polymerization of PVC with a comonomer, for example lactones or other olefins that can polymerize with vinyl chloride and form part of the composition of these resins. Moreover, the term “mastics” means compositions based on polymers or resins in combination with other compounds known by a person skilled in the art, such as plasticizers, fillers and diluents for adjusting the viscosity.
A fourth subject of the invention is the use of the hydrodewaxed diluent alone or in combination with a conventional diluent for the dilution of mastic or of silicone-based adhesives (for example silicone mastics RTV-1 (Room Temperature vulcanizable-1 component) or of modified silicone polymers (SMP: Silane Modified Polymers), for example of type ST-PE (Silane Terminated-PolyEther) or MS polymer (MS=modified silane) or ST-PU (Silane Terminated PolyUrethane). These polymers are mixed with any other compound known by a person skilled in the art, such as plasticizers, mineral fillers, additives, adhesion promoter, catalyst, etc.
The invention can therefore be defined by the following characteristics:
It relates to a hydrocarbon diluent for the dilution of polymer with a pour point below −15° C. according to ASTM standard D97, comprising more than 50% by weight of isoparaffins and naphthenes up to at most 40% by weight, and constituted by a mixture of hydrocarbons with a boiling point above 200° C., obtained by distillation of hydrodewaxed gas-oil cuts.
This diluent preferably has a boiling point comprised between 280 and 450° C.
This diluent preferably has a pour point below −30° C. according to ASTM standard D97.
This diluent preferably has a viscosity greater than 5 mm2/s at 40° C., and in particular greater than 7 mm2/s at 40° C., according to ASTM standard D445.
This diluent is preferably derived from hydrodewaxed hydrocarbons, in particular from the hydrodewaxing of various gas-oil cuts obtained by atmospheric distillation, vacuum distillation, hydrotreating, hydrocracking, catalytic cracking and/or visbreaking, or alternatively products derived from the conversion of biomass, optionally after an additional treatment of desulphurization and/or removal of aromatics.
The composition of this diluent comprises at least 10% by weight of naphthenes.
This diluent is preferably derived from a distillation cut of hydrodewaxed hydrocarbons with a pour point according to ASTM standard D97 below −30° C. and flash point above 140° C.
This diluent preferably comprises from 20 to 35% by weight of naphthenes and more than 60% by weight of isoparaffins.
This diluent preferably comprises more than 65% by weight of isoparaffins and less than 10% by weight of normal paraffins.
This diluent preferably comprises less than 65% by weight of hydrocarbons having a chain length comprised between 16 and 22 carbon atoms, and more than 30% by weight of hydrocarbons having a chain length greater than 22 carbon atoms, preferably from C23 to C30.
This diluent preferably comprises less than 50% by weight of hydrocarbons having a chain length comprised between 16 and 22 carbon atoms, and more than 40% by weight of hydrocarbons having a chain length greater than 22 carbon atoms, preferably from C23 to C30.
This diluent is preferably devoid of normal paraffins.
Its sulphur content is preferably less than 10 ppm, in particular less than 2 ppm.
It preferably contains less than 500 ppm of aromatics, measured by UV spectrometry.
The invention also relates to a composition of diluents comprising the diluents described above in combination with at least one so-called “conventional” diluent, for example belonging to the group comprising acids and esters of fatty acids with carbon chains with more than 16 carbon atoms, cuts of the hydrocracked and/or hydrotreated gas-oil type with a boiling point comprised between 200 and 450° C., in particular comprised between 280 and 450° C., or comprised between 200 and 300° C. This composition preferably comprises more than 50% by weight of isoparaffins and less than 20% by weight of normal paraffins, preferably more than 60% by weight of isoparaffins and less than 10% by weight of normal paraffins. This composition preferably comprises more than 40% by weight of hydrodewaxed diluent, preferably more than 60% by weight.
The invention also relates to a composition of polymer or resin diluted with a diluent as described previously, preferably for construction materials, in particular resins for construction materials, adhesives, floor coverings, wallpapers and mastics, in particular mastics or adhesives based on silicone or modified silicone polymers. The invention also relates to the use of the hydrodewaxed diluent as described previously, alone or in combination with at least one so-called “conventional” diluent, for example belonging to the group comprising acids and esters of fatty acids with carbon chains with more than 16 carbon atoms, hydrotreated and/or hydrocracked cuts of the gas-oil type with a boiling point comprised between 200 and 450° C., in particular comprised between 280 and 450° C., for the dilution of resins for construction materials, in adhesives, floor coverings, wallpapers and mastics, in particular mastics or adhesives based on silicone or modified silicone polymers. The advantages of the present invention are described in the examples given below, which illustrate but do not limit the invention.